Author Nicholas A. Basbanes discusses the remarkable relationship of the celebrated 19th-century poet Henry Wadsworth Longfellow and his wife, Frances Appleton Longfellow, the focus of his recent biography of the couple, Cross of Snow, which is set largely in Boston and Cambridge during the tumultuous years leading up to the Civil War. The couple’s marriage in 1843 represented a melding of two highly gifted and principled people whose shared values and deeply held convictions found expression and purpose in manifold ways, not least of which was the influence Fanny brought to bear on Henry’s creative process, serving, in her words, as “a pretty active spur upon his Pegasus.” Revered in his time as a “poet of the people,” Longfellow’s works were translated into more than 30 languages, memorized by millions of people, with lines that resonate to this day.